So far, ultrasonic motors that drive a driven element such as a rotor, linear actuator, or the like by vibrating a vibrating element are well known. In such an ultrasonic motor, a vibrating element has a piezoelectric element, and undergoes vibration by application of an AC voltage to the piezoelectric element. A technology described in Japanese Laid-Open Patent Publication No. 2000-333480 is known as the above-mentioned technology.
However, in conventional ultrasonic motors, research about a relationship between the size of a vibrating element and reliability of drive or breakage of a drive IC caused by fall is not executed well.